JPH0622290B2 - SSB modulation / demodulation method - Google Patents
SSB modulation / demodulation methodInfo
- Publication number
- JPH0622290B2 JPH0622290B2 JP1261885A JP1261885A JPH0622290B2 JP H0622290 B2 JPH0622290 B2 JP H0622290B2 JP 1261885 A JP1261885 A JP 1261885A JP 1261885 A JP1261885 A JP 1261885A JP H0622290 B2 JPH0622290 B2 JP H0622290B2
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- Japan
- Prior art keywords
- circuit
- signal
- modulation
- frequency
- output signal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- Amplitude Modulation (AREA)
- Reduction Or Emphasis Of Bandwidth Of Signals (AREA)
- Mobile Radio Communication Systems (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、陸上移動無線通信において、無線周波数利用
効率が高く、かつ、高品質な音声信号を伝送するための
ＳＳＢ変復調方式に関するものである。Description: TECHNICAL FIELD The present invention relates to an SSB modulation / demodulation system for transmitting a high-quality voice signal with high radio frequency utilization efficiency in land mobile radio communication. .
ＳＳＢ変復調方式は、原理的に最も狭帯域なものである
が、ＳＳＢ変調波には振幅変調成分があるために、陸上
移動伝ぱん路で用いた場合には、フェージングによって
振幅歪を受ける。The SSB modulation / demodulation method is the narrowest band in principle, but since the SSB modulated wave has an amplitude modulation component, when it is used in a land mobile propagation path, it suffers amplitude distortion due to fading.
そのため、従来、移動無線ではＦＭ変調のように振幅変
調成分の無い変調方式が広く用いられている。Therefore, conventionally, a modulation method without an amplitude modulation component such as FM modulation has been widely used in mobile radio.
ＦＭ変調の場合、必要な無線周波数幅Ｂはカーソン則か
らＢFM＝２（Δf＋f max）となる（但し、Δf は最大周
波数偏移、f max 最高変調周波数）。In the case of FM modulation, the required radio frequency width B is B FM = 2 (Δf + f max) according to Carson's law (where Δf is the maximum frequency deviation, f max maximum modulation frequency).
上述のＦＭ変調方式の場合においては、Δf をいくらか
小さくしてもＢFMの値は２Δf max となる。In the case of the above-described FM modulation method, some values of B FM be smaller the Δf becomes 2.DELTA.f max.
一方、ＳＳＢ変調方式の場合には、ＢSSB ＝f max で良
いから、ＦＭ変調方式はＳＳＢ変調方式に比して、広帯
域になるという問題点があった。On the other hand, in the case of the SSB modulation method, since B SSB = f max is sufficient, the FM modulation method has a problem that it has a wider band than the SSB modulation method.
本発明は、ＳＳＢ変調波の狭帯域特性を損なうことな
く、振幅歪が除去でき、かつ、無歪に信号を復調するこ
とができるＳＳＢ変調方式を提供することを目的とする
ものであって、フェージング等で受ける振幅歪を除去す
るために振幅制限器（以下リミタともいう）を用いると
ともに、復調部でリミタが利用できるように変調された
信号が常に実数零点（ real zeros ）になるように、た
とえば、 full−carrier lower sideband 変調（ＳＳ
Ｂ変調の一部）方式を用いるものである。An object of the present invention is to provide an SSB modulation method capable of removing amplitude distortion and demodulating a signal without distortion without impairing the narrow band characteristic of the SSB modulated wave, An amplitude limiter (hereinafter also referred to as a limiter) is used to remove the amplitude distortion received due to fading, etc., and the signal modulated so that the limiter can be used in the demodulator always has real zeros. For example, full-carrier lower sideband modulation (SS
A part of B modulation) method is used.
以下、本発明の構成等に関し、実施例の図面によって詳
細に説明する。Hereinafter, the configuration and the like of the present invention will be described in detail with reference to the drawings of the embodiments.
第１図は本発明の一実施例のブロック図であって、１は
音声波源、２は局部発振器、３はＳＳＢ変調器、４は加
算回路、５はアップコンバータ、６は送信機、７は送信
アンテナ、８は送信部を表わしている。FIG. 1 is a block diagram of an embodiment of the present invention, in which 1 is a sound wave source, 2 is a local oscillator, 3 is an SSB modulator, 4 is an adder circuit, 5 is an up converter, 6 is a transmitter, and 7 is A transmitting antenna, 8 represents a transmitting unit.
また、９は受信ンテナ、１０はダウン・コンバータ、１
１は中間周波増幅器、１２は振幅制限器（リミタ）、１
３は周波数検波器、１４は−６dＢ／octの等化器、１５
は音声帯域増幅器、１６は音声信号出力端子、１７は受
信部を表わしている。Also, 9 is a reception antenna, 10 is a down converter, and 1 is a down converter.
1 is an intermediate frequency amplifier, 12 is an amplitude limiter (limiter), 1
3 is a frequency detector, 14 is an equalizer of -6 dB / oct, 15
Is a voice band amplifier, 16 is a voice signal output terminal, and 17 is a receiver.
第２図は本発明における歪除去回路の一実施例のブロッ
ク図であって、特許請求の範囲第２項の実施態様に対応
している。FIG. 2 is a block diagram of an embodiment of the distortion removing circuit according to the present invention, and corresponds to the embodiment of claim 2 of the present invention.
第２図において、１８は１４からの信号の入力端子、１
９はヒルベルト変換回路、２０は掛算回路、２１は遅延
回路、２２は減算回路、２３は出力端子を表わしてい
る。In FIG. 2, 18 is an input terminal for a signal from 14, 1
Reference numeral 9 is a Hilbert transform circuit, 20 is a multiplication circuit, 21 is a delay circuit, 22 is a subtraction circuit, and 23 is an output terminal.
実施例の図面を用いて信号の流れに従って本発明の動作
を説明すると、送信部８では、たとえば、３００Ｈz〜
３．０kＨz に帯域制限した音声を入力として局部発振
器２の出力を用い、ＳＳＢ変調器３で下側帯ＳＳＢ変調
波を生成する。The operation of the present invention will be described according to the signal flow with reference to the drawings of the embodiment.
The output of the local oscillator 2 is used with the voice whose band is limited to 3.0 kHz as an input, and the SSB modulator 3 generates a lower side SSB modulated wave.
ＳＳＢ変調波発生法には種々発表されているが、ここで
は、位相法（ phasing method ）を用いた。Various methods have been published for the SSB modulated wave generation method, but here, the phase method is used.
ＳＳＢ変調器３の出力に局部発振器２の出力を加算回路
４にて付加する。これをアップコンバータ、５で無線周
波数に変換したのち送信機６で増幅し、送信アンテナ７
から放射する。受信部１７では、受信アンテナ９で受信
したのちダウン・コンバータ１０で中間周波数帯に変換
し、中間周波増幅器１１で伝ぱん路の損失分を増幅し受
信処理に必要なレベルにする。この出力をリミタ１２に
導入し伝ぱん路で受けた振幅歪を除去する。そして、周
波数検波器１３で検波し音声周波数信号を得る。この周
波数検波器は周波数変調（ＦＭ）方式に用いられるもの
ならすべて利用できる。周波数検波器１３の出力は−６
dＢ／oct の特性をもつ等化器１４で等化する。The addition circuit 4 adds the output of the local oscillator 2 to the output of the SSB modulator 3. This is converted to a radio frequency by an up converter 5 and then amplified by a transmitter 6, and a transmission antenna 7
Radiate from. In the receiving unit 17, the signal is received by the receiving antenna 9 and then converted into the intermediate frequency band by the down converter 10, and the intermediate frequency amplifier 11 amplifies the loss of the propagation path to a level required for the receiving process. This output is introduced to the limiter 12 to remove the amplitude distortion received in the propagation path. Then, it is detected by the frequency detector 13 to obtain an audio frequency signal. This frequency detector can be used as long as it is used in the frequency modulation (FM) method. The output of the frequency detector 13 is -6
Equalization is performed by the equalizer 14 having a characteristic of dB / oct.
等化器１４は、積分器あるいは十分に低いカツトオフ周
波数をもつＬＰＦを利用できる。そして、等化器１４の
出力を音声帯域増幅器１５で増幅して必要なレベルにし
たのち端子１６から取り出す。（周波数検波器としてＰ
ＬＬ（位相同期回路）を用いると次段の等化の機能を含
めることができる。） 次に第２図について説明する。第１図の等化器１４の出
力を入力端子１８から入力して、これをヒルベルト変換
回路１９で変換する。この信号と入力端子１８から直接
導いた信号とを掛算回路２０で掛け合わせる。The equalizer 14 can be an integrator or an LPF with a sufficiently low cutoff frequency. Then, the output of the equalizer 14 is amplified by the voice band amplifier 15 to a required level, and then taken out from the terminal 16. (P as a frequency detector
The use of LL (Phase Synchronous Circuit) can include the equalization function in the next stage. ) Next, FIG. 2 will be described. The output of the equalizer 14 of FIG. 1 is input from the input terminal 18, and this is converted by the Hilbert conversion circuit 19. The multiplication circuit 20 multiplies this signal and the signal directly derived from the input terminal 18.
一方、入力端子１８からの信号をヒルベルト変換回路１
９と掛算回路２０との処理による遅延時間に等しい遅延
時間を有する遅延回路２１を通した後、減算器２２で掛
算器２０の出力との引き算を行なう。On the other hand, the signal from the input terminal 18 is converted into the Hilbert conversion circuit 1
After passing through the delay circuit 21 having a delay time equal to the delay time due to the processing of 9 and the multiplier circuit 20, the subtractor 22 subtracts from the output of the multiplier 20.
実際の装置の遅延回路２１については減算回路２２の出
力をスペクトラム・アナライザ等で観測しながら不要波
が最小になるようにして遅延量を調整することができ
る。With respect to the delay circuit 21 of the actual device, the delay amount can be adjusted by observing the output of the subtraction circuit 22 with a spectrum analyzer or the like so as to minimize unnecessary waves.
更に、本発明の動作原理について説明する。帯域制限さ
れた信号で下側波帯ＳＳＢ変調した信号に搬送波を付加
すると、この信号の零点はすべて実数となる。このた
め、信号の情報はこの実数零点のみによって伝送され
る。そこで、ＳＳＢ信号であっても原音を再生するため
には振幅変調成分は不要となる。このため、移動伝ぱん
路等で受けた振幅歪成分をリミタで除去してもよいこと
になる。Further, the operating principle of the present invention will be described. When a carrier is added to a signal that is SSB-modulated in the lower sideband with a band-limited signal, all zeros of this signal are real numbers. Therefore, the signal information is transmitted only by this real zero. Therefore, the amplitude modulation component is not necessary to reproduce the original sound even with the SSB signal. Therefore, the amplitude distortion component received on the moving propagation path or the like may be removed by the limiter.
次に数式を用いてリミタ出力を周波数検波することによ
って原音が再生できることを説明する。Next, it will be described that the original sound can be reproduced by frequency-detecting the limiter output by using mathematical expressions.
被変調波は Ｓ(t)＝Ａ cos(ω0t＋ω(t)) と書ける。ここで、 となる。ｆ(t) は情報信号、 はｆ(t) のヒルベルト変換である。The modulated wave can be written as S (t) = A cos (ω 0 t + ω (t)). here, Becomes f (t) is the information signal, Is the Hilbert transform of f (t).
次にリミタ（振幅制限器）にＳ(t) を通すと ＳLIM(t)＝cos(ω0ｔ＋ω(t)) と振幅は一定となる。そこで、周波数検波器（周波数弁
別器）で検波する。周波数検波器の機能は数学的には微
分動作で、この出力の低周波成分を取り出せばよい。即
ち、 ここでω(t) は先に与えた式である。又次の公式を利用
する。Next, when S (t) is passed through a limiter (amplitude limiter), S LIM (t) = cos (ω 0 t + ω (t)) and the amplitude becomes constant. Therefore, detection is performed by a frequency detector (frequency discriminator). The function of the frequency detector is mathematically a differential operation, and the low frequency component of this output may be extracted. That is, Where ω (t) is the equation given earlier. Also use the following formula:
以上の準備のもとに周波数検波器出力は、 となる。ここで−６dB／oct の等化を積分動作で行なう
と、 となる。但しＤＣ成分は除去したのちに積分している。
ここで が得られる。すなわち、原音が再生できる。 Based on the above preparations, the frequency detector output is Becomes Here, if equalization of -6 dB / oct is performed by the integration operation, Becomes However, the DC component is removed and then integrated.
here Is obtained. That is, the original sound can be reproduced.
第２図の歪除去回路は上式の２次の歪 を除去するためのものである。The distortion elimination circuit of FIG. 2 is the second-order distortion of the above equation. Is for removing.
第２図において、ヒルベルト変換回路１９の入力を とすると、その出力は−ｆ(t) となる。そこで、掛算回
路２０で を作る。これを入力端子１８の信号 から引くことによって、２次歪のない が得られることが分かる。In FIG. 2, the input of the Hilbert conversion circuit 19 is Then, the output becomes -f (t). Therefore, in the multiplication circuit 20, make. This is the signal of the input terminal 18 There is no secondary distortion by subtracting from It turns out that
以上説明したように、本発明の方式によれば、ＳＳＢ変
調信号でありながら、受信部に移動伝ぱん路で受けた振
幅歪を除去するためのリミタが挿入でき、良好な復調信
号が得られる利点がある。しかも、ＳＳＢ変調波である
から、伝送に必要な無線周波数帯域幅は各種の変調方式
の中で最も狭いという利点があるので、移動通信方式な
どの周波数有効利用効率を重視する通信系に適用するこ
とにより、大きな効果が得られる。As described above, according to the method of the present invention, although it is an SSB modulated signal, a limiter for removing the amplitude distortion received in the moving propagation path can be inserted in the receiving section, and a good demodulated signal can be obtained. There are advantages. Moreover, since it is an SSB modulated wave, it has the advantage that the radio frequency bandwidth required for transmission is the narrowest of the various modulation methods, so it is applied to communication systems such as mobile communication systems that place importance on effective frequency utilization efficiency. As a result, a great effect can be obtained.
第１図は本発明の一実施例のブロック図、第２図は本発
明における歪除去回路の一実施例のブロック図である。 １……音声波源、２……局部発振器、３……ＳＳＢ変調
器、４……加算回路、５……アップコンバータ、６……
送信機、７……送信アンテナ、８……送信部、９……受
信アンテナ、１０……ダウンコンバータ、１１……中間
周波増幅器、１２……振幅制限器（リミタ）、１３……
周波数検波器、１４……等化器、１５……音声帯域増幅
器、１６……音声信号出力端子、１７……受信部、１８
……入力端子、１９……ヒルベルト変換回路、２０……
掛算回路、２１……遅延回路、２２……減算回路、２３
……出力端子FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of an embodiment of a distortion removal circuit of the present invention. 1 ... Voice wave source, 2 ... local oscillator, 3 ... SSB modulator, 4 ... adding circuit, 5 ... up converter, 6 ...
Transmitter, 7 ... Transmission antenna, 8 ... Transmission section, 9 ... Reception antenna, 10 ... Down converter, 11 ... Intermediate frequency amplifier, 12 ... Amplitude limiter (limiter), 13 ...
Frequency detector, 14 ... Equalizer, 15 ... Voice band amplifier, 16 ... Voice signal output terminal, 17 ... Receiver, 18
...... Input terminal, 19 ...... Hilbert conversion circuit, 20 ……
Multiplication circuit, 21 ... Delay circuit, 22 ... Subtraction circuit, 23
...... Output terminal
Claims (2)
路と、 該周波数変換回路の出力信号を電力増幅して出力する送
信回路とを設け、 受信側に、受信信号の振幅を一定にする振幅制限回路
と、 該振幅制限回路の出力信号を検波して音声信号を得る周
波数検波回路、若しくは、周波数検波回路と等化器とよ
り成る回路とを具備することを特徴とするＳＳＢ変復調
方式。1. In a carrier wave band analog communication system, a transmitting side is provided with a modulation circuit for performing SSB modulation with an audio signal, an addition circuit for giving a carrier wave to an output signal of the modulation circuit, and a frequency of an output signal of the addition circuit. A frequency conversion circuit for converting and a transmission circuit for power-amplifying and outputting the output signal of the frequency conversion circuit are provided, and an amplitude limiting circuit for making the amplitude of the received signal constant on the receiving side, and an output of the amplitude limiting circuit An SSB modulation / demodulation system comprising a frequency detection circuit for detecting a signal to obtain an audio signal, or a circuit including a frequency detection circuit and an equalizer.
化して得られた音声信号を遅延せしめる遅延回路と、 該音声信号をヒルベルト変換するヒルベルト変換回路
と、 該ヒルベルト変換回路の入力である音声信号と該ヒルベ
ルト変換回路の出力信号とを掛け合わせる掛算回路と、 該掛算回路の出力信号と前記遅延回路の出力信号とを減
算して出力する減算回路とを具備する特許請求の範囲第
(1)項記載のＳＳＢ変復調方式。2. A delay circuit for delaying a voice signal obtained by frequency detection on the receiving side or equalizing the same, a Hilbert transform circuit for Hilbert transforming the voice signal, and an input of the Hilbert transform circuit. 7. A claim, comprising: a multiplication circuit for multiplying an audio signal and an output signal of the Hilbert conversion circuit; and a subtraction circuit for subtracting and outputting the output signal of the multiplication circuit and the output signal of the delay circuit.
The SSB modulation / demodulation method described in (1).
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1261885A JPH0622290B2 (en) | 1985-01-28 | 1985-01-28 | SSB modulation / demodulation method |
| DE8585308784T DE3585502D1 (en) | 1984-12-10 | 1985-12-03 | SINGLE-SIDED TAPE TRANSFER SYSTEM. |
| EP85308784A EP0184923B1 (en) | 1984-12-10 | 1985-12-03 | Single-sideband communication system |
| US06/806,991 US4803739A (en) | 1984-12-10 | 1985-12-09 | SSB communication system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1261885A JPH0622290B2 (en) | 1985-01-28 | 1985-01-28 | SSB modulation / demodulation method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61172413A JPS61172413A (en) | 1986-08-04 |
| JPH0622290B2 true JPH0622290B2 (en) | 1994-03-23 |
Family
ID=11810361
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1261885A Expired - Lifetime JPH0622290B2 (en) | 1984-12-10 | 1985-01-28 | SSB modulation / demodulation method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0622290B2 (en) |
-
1985
- 1985-01-28 JP JP1261885A patent/JPH0622290B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61172413A (en) | 1986-08-04 |
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| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |